125
TROUBLESHOOTING
Engine Troubleshooting
Problem
Probable Cause
Solution
Engine turns but fails
to start
Faulty ignition
• Install new spark plug(s). If engine
still fails to start, check for spark. If
there's no spark, SEE YOUR
DEALER.
No fuel to engine
• Make sure the fuel valve is on.
• Make sure the fuel tank contains
fuel.
• Ice may be in the fuel line, filter or
pump. Add isopropyl alcohol to the
fuel system.
Poor engine com-
pression
• Mixture is too lean. A main jet that
is too small will cause seizure result-
ing in loss of power. This indicates a
major engine problem that must be
repaired before operating. SEE
YOUR DEALER.
Engine lacks power
Fouled or defective
spark plug(s)
• Replace the plug(s).
Fuel filter (loss of
high RPM power)
• SEE YOUR DEALER.
Incorrect clutching
• SEE YOUR DEALER.
Engine continually
backfires
Faulty plug(s)
• Change plug(s).
Fuel System
• Dirt or ice may be in the fuel system
(deicer should be added to non-
ethanol fuel at all times for
assurance against fuel line icing).
Incorrect throttle
freeplay or faulty
switch
• SEE YOUR DEALER.
Engine requires
more than normal
pulls to start
Poor fuel
• Replace with fresh winter fuel.
Not enough fuel get-
ting to engine
• SEE YOUR DEALER.
Engine backfires but
fails to start
Spark plug wires
may be on wrong
cylinder
• Reinstall spark plug wires to the
corresponding cylinder.
